Is heart disease in chronic epilepsy a consequence of seizures or a fellow traveler?

Epilepsy is associated with an increased incidence of heart failure diagnoses

OBJECTIVE

Epilepsy is a complex disease with serious consequences for the quality of life and prognosis of those affected. The importance of comorbidities in disease progression and prognosis has gained increasing recognition in recent years. In the present study, we investigated the potential association between epilepsy and heart failure in an outpatient cohort in Germany.

METHODS

Using the IQVIA Disease Analyzer database, we identified a total of 9646 patients with late-onset epilepsy and a matched cohort of equal size without late-onset epilepsy who were followed up between 2005 and 2018. Cox regression models were used to evaluate the potential association between epilepsy and heart failure.

RESULTS

Within 10 years of the index date, 28.6% of patients with epilepsy and 20.4% of patients without epilepsy had been diagnosed with HF (log-rank p < 0.001). The incidences were 36.3 cases per 1,000 patient years in the epilepsy cohort versus 23.1 cases in the non-epilepsy cohort. In regression analyses, epilepsy was significantly associated with the incidence of HF (Hazard Ratio (HR): 1.56, p < 0.001). The association was somewhat stronger in men (HR: 1.63, p < 0.001) than in women (HR: 1.49, p < 0.001). The HR in the epilepsy group decreased with increasing age.

CONCLUSION

Our study provides strong evidence that epilepsy is associated with an increased incidence of heart failure. This finding should help raise awareness of this important comorbidity and could trigger specific cardiovascular screening programs in patients with epilepsy.

Epileptic heart: A clinical syndromic approach

Prevention of premature death in patients with chronic epilepsy remains a major challenge. Multiple pathophysiologic factors have been implicated, with intense investigation of cardiorespiratory mechanisms. Up to four in five patients with chronic epilepsy exhibit cardiovascular comorbidities. These findings led us to propose the concept of an "epileptic heart," defined as "a heart and coronary vasculature damaged by chronic epilepsy as a result of repeated surges in catecholamines and hypoxemia leading to electrical and mechanical dysfunction." Among the most prominent changes documented in the literature are high incidence of myocardial infarction and arrhythmia, altered autonomic tone, diastolic dysfunction, hyperlipidemia, and accelerated atherosclerosis. This suite of pathologic changes prompted us to propose for the first time in this review a syndromic approach for improved clinical detection of the epileptic heart condition. In this review, we discuss the key pathophysiologic mechanisms underlying the candidate criteria along with standard and novel techniques that permit evaluation of each of these factors. Specifically, we present evidence of the utility of standard 12-lead, ambulatory, and multiday patch-based electrocardiograms, along with measures of cardiac electrical instability, including T-wave alternans, heart rate variability to detect altered autonomic tone, echocardiography to detect diastolic dysfunction, and plasma biomarkers for assessing hyperlipidemia and accelerated atherosclerosis. Ultimately, the proposed clinical syndromic approach is intended to improve monitoring and evaluation of cardiac risk in patients with chronic epilepsy to foster improved therapeutic strategies to reduce premature cardiac death.

The Epileptic Heart: Concept and clinical evidence

Sudden unexpected death in epilepsy (SUDEP) is generally considered to result from a seizure, typically convulsive and usually but not always occurring during sleep, followed by a sequence of events in the postictal period starting with respiratory distress and progressing to eventual cardiac asystole and death. Yet, recent community-based studies indicate a 3-fold greater incidence of sudden cardiac death in patients with chronic epilepsy than in the general population, and that in 66% of cases, the cardiac arrest occurred during routine daily activity and without a temporal relationship with a typical seizure. To distinguish a primarily cardiac cause of death in patients with epilepsy from the above description of SUDEP, we propose the concept of the "Epileptic Heart" as "a heart and coronary vasculature damaged by chronic epilepsy as a result of repeated surges in catecholamines and hypoxemia leading to electrical and mechanical dysfunction." This review starts with an overview of the pathophysiological and other lines of evidence supporting the biological plausibility of the Epileptic Heart, followed by a description of tools that have been used to generate new electrocardiogram (EKG)-derived data in patients with epilepsy that strongly support the Epileptic Heart concept and its propensity to cause sudden cardiac death in patients with epilepsy independent of an immediately preceding seizure.

Physical fitness levels and moderators in people with epilepsy: A systematic review and meta-analysis

Cardiorespiratory fitness (CRF) is a modifiable risk factor for mental and physical chronic conditions and premature mortality. Cardiorespiratory fitness levels and moderators among people living with epilepsy are unknown. The aim of the current meta-analysis was to (1) determine mean CRF in people living with epilepsy and compare levels with age- and gender-matched healthy controls (HCs), and (2) explore moderators of CRF. Major electronic databases were searched systematically for articles reporting CRF expressed as maximum or peak oxygen uptake (ml/min/kg). A random effects meta-analysis calculating the pooled mean CRF including subgroup- and meta-regression analyses was undertaken. Across 4 studies, the CRF level was 31.4 ml/kg/min (95% confidence interval [CI] = 27.3 to 35.5) (n = 121; mean age = 29-43 years). Compared with age- and gender-matched controls (n = 39), in people with epilepsy (n = 39), CRF levels were 4.9 ml/kg/min (95%CI = -5.9 to -3.9) lower (P < 0.001). Cardiorespiratory fitness levels obtained via maximal tests were significantly (P < 0.001) lower than obtained via submaximal tests. Future research should explore underlying mechanisms for the observed impairment in CRF in people with epilepsy.

Comorbidity between epilepsy and cardiac arrhythmias: Implication for treatment

Epilepsy is often comorbid with either neurological or nonneurological diseases. The association between epilepsy and cardiac arrhythmias is not infrequent, mostly in patients with severe forms of epilepsy or critically ill. Remarkably, these medical conditions share many similarities. Vascular and genetic disorders may predispose to both seizures and abnormalities of cardiac electrophysiology. Repeated and uncontrolled seizures may favor potentially life-threatening arrhythmias. Antiepileptic drugs (AEDs) may facilitate the occurrence of cardiac arrhythmias by acting on ionic channels at heart level. Antiarrhythmic drugs (AADs) can have effects on ionic channels expressed in the brain, as suggested by their efficacy in treating patients with rare forms of epilepsy; AADs may also be proconvulsant, mainly during their overdosage. In clinical practice, the AEDs with the lowest risk to influence cardiac electrophysiology are to be preferred in patients presenting with either seizures or arrhythmias. Traditional AEDs should be avoided because of their arrhythmogenic properties and enzyme-inducing effects, which may make ineffective the concomitant treatment with AADs. Some of the newer AEDs can rarely affect cardiac rhythm, and electrocardiogram (ECG) monitoring should be warranted.

Repeated generalized seizures can produce calcified cardiac lesions in DBA/1 mice

Studies suggest that cardiorespiratory dysfunction likely contributes to sudden unexpected death in epilepsy (SUDEP). Seizures result in autonomic and respiratory dysfunction, leading to sympathetic hyperactivity and respiratory distress, including apnea. While the heart is vulnerable to catecholamine surges and hypoxia, it remains unknown if repetitive generalized seizures lead to cardiac damage. DBA/1 mice exhibit seizure-induced respiratory arrest (S-IRA) following generalized audiogenic seizures (AGS), which can be resuscitated using a rodent ventilator. In the current study, we induced different numbers of S-IRA episodes in DBA/1 mice and determined the association of repeated S-IRA induction with cardiac damage using histology. After repetitive induction of 18 S-IRA, calcified lesions, as revealed by calcium (Ca²⁺)-specific alizarin red staining, were observed in the ventricular myocardium in 61.5% of DBA/1 mice, which was higher compared to mice with 5 S-IRA and 1 S-IRA as well as age-matched untested control mice. The incidence of lesions in mice with 9 S-IRA was only higher than that of control mice. Only 1-2, small lesions were observed in mice with 5 S-IRA and 1 S-IRA and in control mice. Larger lesions (>2500 μm²) were observed in mice with 9 and 18 S-IRA. The incidence of larger lesions was higher in mice with 18 S-IRA (53.8%) as compared to mice with 5 S-IRA and 1 S-IRA as well as with control mice, and the incidence of larger lesions in mice with 9 S-IRA was only higher than that of control mice. Repeated induction of S-IRA in DBA/1 mice can result in calcified necrotic lesions in the ventricles of the heart, and their incidence and size are dependent on the total number of S-IRA.